Process of refining petroleum hydrocarbons



Oct. 28, 1941. w. T. HANCOCK PROCESS OF REFINING PETROLEUM HYDROCARBONS Filed Nov. A27, 1959 NNNQ .4| Qn, I, v I l www. t ,wh\ I l j h? M NQR Patented Oct. 28, 1941 UNITED .STATE -rRooEssfoF .HimnocAmsoNsv 1 william mnancock, Longl Beach, oem, .,ApplcationNovember 27,1939; SerialN0.306;347" l 12 claims.. (omas- 147) This invention `has to do generally with the rening of petroleum hydrocarbons, and isfconcerned' particularly with an improved system' for treatingA cracked pressure distillate for the pur pose of removing polymers and gum forming impurities, and further if desired, to materially increase the yield of gasoline or other'relatively vvaluable fractions, by additional conversion :and treatment of polymerized-constituents.

In one of its general aspects, the invention has for its object to providean improved method for subjecting hydrocarbons to polymerization by treatment with adsorptive material, such asrone or a mixture of known adsorptive clays, andreferred to hereinafter typically as a-clay. The;

present system is particularly directed toflthe polymerization of unsaturated hydrocarbons in liquid or mixed liquid and vapor phase, land inA this aspect improves upon past methods in "one respect, among others, that the effective life'of.

the adsorbent material is considerably prolonged by the manner in which the polymers are re` moved from the clay and prevented fromrcontaminating the clay under'such conditions as ordinarily occur by flowing the distillate A`and Asi 'previously indicated; the invention also contemplatesv utilizing :the polymerized hydro- `carbons byffsubje'cting Athem to reconversion and Y treatment-to produce' gasoline-'and other valuable"fractions,` 'For' this purpose; the polymers,

` tillate Vflowing therethrough.

contained polymers together throughA the clay. l

Briey stated the present methodavoidslthe usual degree of polymer contamination of 'thev clay, by providing for gravity separation and settling out of the heavier polymerized compounds from the location of their formation in the clay,

all in a manner such that the polymers are not required to pass through other portions ofthe clay body beyond such locations.

The present system also embodies various limprovements in the general type of treating-system disclosed in Patent Number '2,162,715,--is

sued June 20, 1939, to me on Process 4for rening cracked petroleum distillate. According tothat system, heated gasoline-containing pressureY distillate is subjected topolymerization by passage through a body of adsorptive material, and then is admixed with heated heavier or solvent oil from which gasoline and other fractions are recovered by vaporiz'ation, leaving `gum-forming constituents of the distillate being treated, remaining in the heavy solvent oil. Inv accordance with the present invention, -gum forming constituents of the pressure distillate that become polymerized by treatment with clay, are removed from the distillate stream prior to mixing it with the heavier oil, thus preventing overloading of the latter and and 'efficiency distillate.

increasing the 'degree' of polymer extraction from thel e Vinventionincludes --var1ous `additional objects and details; but'these as well as the features `generally discussed inthe foregoing will be 'explained to better advantage by describing the- .system illustrated in V'the accompanying drawingl and representing a typical system embodying theinventiom shown diagrammatically and in-`iiow^sheet form'.

Referring toy the drawing,- suitable means shown'typicallyas `a clay containing column or ltower generally indicated at I0, is provided for subjecting gasoline-containing heated pressure distillate to,` polymerization under conditions laterdescribed more vinvdetail. It is tobe understood that 'in the broad-aspects of thein-k l vention, the pressure distillatel fed tothefclay column I0 may bederivedl from any suitable source; and -that lit mayv have any. desired boiling'range. As illustrative, I may lfeed to the clay tower pressure` distillate having a boiling range from 90 l,F.to l425 heated to a suit.-y

Aable-temperature at which propery polymerization'will occur in the tower, which temperature usuallyv will be in excess of 200 F. and preferably in-the neighborhoodv of 3509 F. to 375 F., or

` above. y

yAs -illustratedfthe pressure distillate may be takenv from a source ofsupply, such as the stor-` age tank I I, through -line I2to a heater I3 wherein the oil is heated to proper polymerizing temdirect from a. suitable cracking plant generally indicated at I'I. This cracking plant may be one of I any Vknown type and construction .for `proby means of which the cracked pressure distilf late is produced. This fractionating apparatus?" 25 is shown typically to comprise-a dephlegmatori or fractionating column 2B from the baseofj which relatively high boiling hydrocarbons within the fuel oil range, or above,"are withdrawn' through line 21 and recirulated Athrough line;

28 to the cracking still. The overhead Vvvapors are discharged through line 29 into fractionat--' ing column ltlfroin the baseof which the pressure distillate is discharged through lines 3| and l0 to the clay tower IIJ. VFixed and uncondensibleV gases leaving column 30 through line 32 may be further treated or disposed of as desired. The charging stock may be fed to coil 33 in the cracking still I8 throughline ISand the reflux condensate returned through line 28 yand subjected to cracking in an yindependent coil 34; or the cracking still charging stock may be sup,- plied through line 20 so that the charging stock and reflux condensatewill be combined and subjected to cracking in the same coil 34... The clay tower I0 is chargedl with a body 36 of suitable adsorptive material, preferably .adsorptive clay such as fullers earth, Muroc and- Death Valley clay, which `may be` treated with acid or other electrolyte to increase its normal effectiveness as a polymerizingimedium, all in a manner familiar to thoseiskilledin the art. The heated pressure distillate is introduced to the clay body 3B through line I5, the outlet i5a of which preferably is positioned at an intermediate depth in the clay bed and directed so that the distillate is caused to flow upwardly within the clay. Y When subjected to the action of the clay, the ldistillate undergoes polymerization, with the resultant formation of relatively heavy or-high-boiling polymers which, as is known, are dark colored,

gum-forming compounds desirably removable asy impurities from the distillate and nal .gasoline product. The diameter of .shell 31- is -made`I sufciently large, relative to the-distillate through-v put, that the rate of upward flow of thel distillate. will be sufciently slow to permit gravity-settling of the heavy polymers to the bottom of the clay body and into the drain` discharge line 38. `The rate of discharge of polymers or polymer.` containing distillate through line `38 may be regu lated by a suitable valve control, conventionally illustrated at 39, whereby the rate of draw-off from the clay tower may be governed in -accordance with the quantity and rate vof polymer formation. By thus providing for settling and,

drainage of polymers from the body of clay,` ther effective life of the clay-is materially prolonged,

since the polymers, or 'at least allof the polymerized bodies, are prevented from being carried; by the distillate through the entire body of clay. Instead, as the polymers are'formed, they tend to settle and gravitate to the vbottom' of the tower, without passing through-the portion of Atheclay body abovethe location of their-formation..

For the purpose offurther treatment, the rela-3 tively polymer-free distillatemay be discharged from the clay tower I0 through line 40 and introduced at 4I into a suitable mixing chamber 42, shown to comprise a shell 43 provided with mixing baliies 44, to be intimately admixed with a heated heavier oil. This heavier oil may be of any suitable type and composition containing at least a substantial portion of hydrocarbon fractions of higher boiling range than the gasoline contained in the pressure distillate removed from the clay tower through line 40. Typically, the heavier oil may consist of a crude oil, with or without considerable gasoline fractions, or an untreated fuel oil or gas oil, or combination of both. j The heavier oil, taken from a suitable supply source. `through line 45, is pumped through a `heater 46 wherein the oil is pre-heated to a temperature preferably in excess of the temperature of lthe pressure distillate being introduced to mixer 42, and preferably to a temperature ranging vfrom 500 F. to 600 F.

4 The 4pre-I fieated heavier oil is discharged through Vline y4I to be combined or admixed in the chamber 42 with the clay treated pressure distillate, ordinarily in the proportion of from-two to four parts of the heavier oil to one part of the pressure distillate, Valve 48 in the mixerdischarge line 49 is set to maintain sufficientback pressure that at least a major portion of the oils being mixed, and preferably a major portion of the gasoline content thereof, will remain Ain liquid phaserduring the mixing.

The admixed oils are discharged through line 49-to a dephlegmator or fractionating column 50 wherein the lighter fractions, say through the `gas oil range, ofthe mixed oils are suitably separated or vaporized, as by iiash vaporization due to pressure reduction at the Valve 48, the dephlegmator preferably being maintained under com paratively low pressure, for example under 25 lbs. per sq; in. gauge. A steam coil 5I in the base of the dephlegmator, may be used to further deplete the unvaporized residue in the bottom of the dephlegmator, of any light fractions remaining in the residue. As explained more fully and in detail in my issued patent referred to above, admixing the polymerizedpressure distillate taken from-,the clay tower through line 40, with 'the heatedoil flowing from line 41, causes the heavier oil to serve as a solvent or retaining mediumfor any heavier gum-forming and sulphur containing compounds Acarried out from the clay tower in the distillatestream. After flash vaporization of the admixture in dephlegmator 50, such gum-forming and sulphur lcompounds are retained within the 'unvaporized oil and withdrawnrfor recirculationV to the cracking still through line 62.

...The `vapors .flow from the dephlegmator 5D through `line 52 into fractionating column 53, Which'may be regarded as typical of any suitable apparatus for subjecting the vapors to nal fractionation and condensation. A relatively heavy fraction,such as gas oil, may berremoved from the base of rcolumn 53 through line 54, `a next lighter` fraction containing Vkerosene. distillate may be removed from the upper section of the column through line 55, and the vaporspassed through 56 to a condenser 51from which the productigasolineilows through line 58, to a re-v ceiver 59 fixed gases. being taken offthrough line 60. i

. In i addition to the -feature off-prolonging the` useful life of the clay by removal of polymers inthe manner described, the invention contemplates further economy and advantagein .providing for.` recirculation and cracking of the polymers withUv drawn from the cliayftower 'to-convert theipoly.- mers pinto. gasolineA or other useable;V fractions. Thus as illustrated, the; polymer.; containing streamwithdrawn-irom the clay tower-Loman be returned v.throng-hline 6 I to the Y cracking,` still yi8, and recirculated through coil 34 ,together'iw-ith chargingr stock supplied through line `2001 independently circulated through #coil 34 .in instances n wheree thel -chargingv stock is ,independently cracked in coil ;33. 'The' polymer` stream in line 38Halso rnay,lif desired, be v.combined for ,recirculation to the .cracking still 4with .unvaporized oil or residue kwithdrawn from the-basefof: dephlegmator-Sv through lineZ. f As will vbeunderstoodp,k this residue comprises they higher boiling fractions of the adrnixed pressure distillate vand heavier oi l ,supplied from the heater 46that remain unvaporized after.. being introduced through i line IHite thedephlegmator. llhe feature of subjecting the polymers and sulphur compound: containing ;unvaporlzed .solvent oil to cracking` more specicallydealt Awith and broadly claimed in/ mycopen'dingaplication ASerfNo. 327,198, filed April l, `1940, on O il refiningand treating system,

4 .In addition to increasing the potential yieldpof cracked gasoline from the charging stock, recirculation of polymers from iclay tower la through lines 38 and -Sl to the cracking still has the, furtheradvantage of 'converting organically combinedy sulphur to.; gaseous, forms *which are bodyZf/of'zi; adsorptive cmaterial; `wherein, polymers arelormedpallowing relatively high-boiling polymers; .to gravitatetviith-lnz' fthe liquid 'distillate .f in y said body of material toward ,the bottom thereof, separately 4withdrawingfffromzsaid bodyv ot" materia] a'. streamvofisai'd: liquid: .distillate having rel;`

- atifve'lyf. low.".polymerscontent v and as strean'rof:r the liquidxdistillatezfthat is'relatively 'highiinzpolymer content, subjecting' "the: lastl 'mentioned' y stream'- of; distillate: .1 to..` cracking, x andzreturni-ng:

' the. .resulting cracked lhydrocarbons to said. body of adsorptive material in liquid. phase.

i ,5..1'Ihewprocess oi..1reiining petroleum hydrocarbons thataincludeszsubjecting heatedg'asolinecontaining;crackedapetroleuni, 'distillate to: polye removable fromthe system as fixed gases through l line 60. For example, polymers containing lor-A v ganically combined sulpl'iurv recirculatedfrom `the clay towerr to the cracking still are dissociated to form recoverable` gasoline fractionsv .and fixedi gases such as sulphur dioxide and hydrogen sul-- iide,y which, passen through the system in uncondensible form. and sulphur compounds removed from the pressure distillate-solvent oil mixture introduced into. dephlegmator 50, by retention inthe unvaporized oil recirculated to the cracking stillthrough'line 62, are subjected to conversion into recoverable gasoline fractions and iixed gasesin the cracking andsubsequent rtreating stages. f

eI claim:

.1.y The process carhons that includes subjecting heated` gasolinecontaining ,cracked petroleum distillate yto poly meriaationby passing the liquid distillatevinto ya body-of adsorptive material wherein polymers are ii'Or-med,y allowing vrelatively high-boiling polymers to gravitate within the liquiddistillate in said body of, materialtoward -thebottom thereof,

and separately withdravvingl from said body ofV` material a stream of said liquid distillate having relatively low polymer content and a stream ofv the liquid distillate that `is* relatively highy in polymer content. y. ,Y

2. The process `of refining petroleum hydrocarbons that includes subjecting heated gasolinecontaining cracked petroleum distillate to polymerization by passing the liquid distillate into and upwardly within a body of adsorptive material wherein polymers are formed, allowing rela- In, a similar mannenrpolymers:

vof refining petroleum; hydromeri'zation by` passingtheyliquidz. distillate into. a body kof adsorptive; materialiwhereinf .polymers are l formed, -i allowing yrelatively f .high-boiling.

t pcliimesfrto .-gravitate: .within 'the liquid distillate lin said body of materialftoward the4 bottomk thereof; separately'fwithdrawingifrom said body' of.'

material.,l a.' stream ,of 'isaidli'quim distillate havinglfrelatively lovv.V polymer content and a stream off-.fthe liquidl distillate that .is relatively high inv polymer-.content `:mixing :saidrelatively low poly-l merscontent; stream .with heated vheavier oil hav-' i ing a substantially*higherboilingrange than said gasoline,i ivaporizi-n'g; `said :gasoline :from l the.

heavierioili toijleave: impurities of .the distillatev in an. unvaporized rresidual'. oil, subiecting said residualoiland caldirelativelye'high;,polymer content tively high-boiling polymers to gravitate within the liquid distillate in said body of material toward the bottom thereof, withdrawing from the top of said material a stream of said liquid distillate having relatively low polymer content, and withdrawing from the bottom of said material a separate stream of the liquid distillate that is relatively high in polymer content.

3. The process of refining petroleum hydrostream; of disl'fillatev togcracking, and yreturning thefresulting;:cracked2y hydrocarbons to saidcbody. Y

of ladsorptive material-in. liquidphase. x Y y.

6; Ihefprocess' ofzren'ing petroleum hydrocarbons,4v that Lincludes' .subjecting heated v.gasolinecontaining crackedr petroleum." distillate r`:tol lpolymerlzationbypassing'meliquidxdistillate into a I bodyf-aot adsorptiyes materiali A,wherein polymers are forme.d, allowing; 'relatively' high-,boiling polymers-tolA gravitate withinthe` liquid distillate".` in i saidv vbody :.of. material :toward the bottom thereof, separately withdrawingzfrom said body off material; a'stream .fof Hsaid liquid distillate. having relativelyflowfpolymer content 'and astream of theliquid .distillatethat, is; relatively highl in polymer eontentgpmixing; said relatively low. polynierv Ioranti-int stream ,with heatedheavier oil hav-p ing a substantially higher boiling range than said gasoline, vaporizing said"A gasoline from the heavier oil tovleave impurities'of the distillate in an unvaporized residual oil, combining said residual oil and said relatively high polymer content stream'of distillate, subjecting the comy bined oils to cracking,` and returning the resulting cracked hydrocarbons to said body of adsorptive material in liquid phase.

7. The process of refining petroleum hydrocarbons that includes subjecting heated gasoline v containing cracked pet'rleum distillate to polymerization` .'by.: passing the Yliquid f distillate f into andi upwardly within arbodyof radsorptive materialiwherein polymers are `formed, allowing relatively "high-boiling polymers Vto gravitate with/- in. the-liquid distillate .within said body of rmaterialv toward the bottom -thereof, withdrawing from the V top of-said'material a stream .of said liquid'fdistillate having.- relatively low polymer content-mixing said`r relatively low polymer content streamyvith heatedA heavier oil having a substantially higherboiling range than said gasoline, vaporizing' said l' gasoline ifrox'n'.` the heavier. oil to leave. impurities -ofilthezdistillate in .arr-unva-r porized 'residual oil, subjecting:r said residual'. and said relatively .high polymer ycontent stream,v of distillate tocraokin'g, "andi-'returningfa. gasoline' containing; .fl-iquid fraction of the resulting.

cracked hydrbcarbons-to f saidfbody of a'dsorptive.

material...

- 8.. The process :ofi: refining ,'.petroleum carbons Jthat includes' subjecting'heated gasoline-l Containing `cracked.petroleum distillateto 4poly-v merization` by z cont'acting: the,.liquid` distillatel with adsorptive material; .separating-.from said material alstreamof t-heiuiliquid; distillateA havl-e ing relatively: low: polymer? content, separatirlg= from the material anotherstream of .the liquid distillate that is relativelyihigh.ingpolymerlcontent, subjecting the`v z last ,1 'mentioned 'stream ,of distillate "to Il cracking.. and. ssubjectingaai i. liquid gasoline containing*iractionI ofl th'ejresiultingy cracked Al'iydroca'rboi'fis;to .polymerization `by -said adsorptive materiali together? .with said distillate..

9.2The process ofszrening petroleum; hydrocarbons? thatincludesil subjecting heated gasolineicontaining crackedipetrol'eum' distillate t`o= polymerization by: contacting `the 'liquididistillate.7 with` adsorptivematerial, vseparating `from said material `a stream ofthe distillate havingy relaL-w.

tively low polymer content,'. separating from vthe material anotherlstreamfofvthe `distillate that is: relatively high in'polymerfcontent, mixing said relatively. low polymer content stream .with heated heavier oil having'a substantially. higher boiling range' than said .'gasoline, vaporizing-'said gasoline fromthe heavierzoilr'to leave impurities,r of the `:distillate in ,an unvaporized residual oil,. subjecting saidxresidualfoilf'and said relatively high polymer" content st-reain of distillate t'ov cracking, 'and contacting .La gasoline i containing fraction of .the resultingfcracked productsy withv said adsorptivezmaterial.

10. The process .off re'ning petroleum hydro- I carbons rthat :includes: subjecting petroleum-f tof cracking, polymerizing:gasolineicontaiing heat'- J ed distillateproduced thereby-by Spassing the 'liqy uid distillate `intoU-aibody of 'adsorptfve Vr'naterial wherein polymers are formedyallcwing relativelyV high-boiling polymers* to s gravitat'e 'within Ithe i liquid.- distillate in said body .offm'aterialx toward y the bottom thereof, separately withdrawing from said body. of' mate'riala` stream of said liquidldis# tillate Ihaving relativelyllorvvr` poly-mercontent." and a .stream of the'liquid distillate that is relatively high. :in `polymer content,` subjecting the last mentioned distillate to cracking and returning a 'gasoline-containing liquid fraction of the resulting cracked hydrocarbons to said body of ad-v sorptive material.

11.` 'Ihe process of refining petroleum oil that includes,` subjecting 'the voil to cracking in a cracking zone', subjecting the hydrocarbons from said cracking zone to fractionation'to produce relatively heavy residuum, gasoline-containing pressuredistillate, and uncondensed gases, passing the liquid distillate into a body of adsorptive material wherein polymers are formed, allowing relatively high-boiling polymers to gravitate within the liquid distillate in said body of material toward the bottom thereof, separately withdrawing fromfsaid body of material a stream ofY said distillate having relatively 10W polymer content and a `stream of the distillate thatfis relatively high in poylmer content, passing through a heating zone a stream of solvent oil having aboiling lrange substantially higher4 than that of thegasoline content of the pressure distillate, mixing the heated solvent oil with said relatively low polymer content stream of the polymerized pressure distillate, vaporizing and separating the gasoline fromv the unvaporized solvent oil in a vaporizing zone, thereby leaving gum-forming and sulphur-containing impurities of the distillate in said solvent oil, and passing said solvent oil from the vaporizing zone tc'said cracking zone as preheated charging stock.

l2. The process of refining petroleum oil that includes,l subjecting the oil tocracking ina cracking Zone, subjecting the hydrocarbons from said cracking zone to fractionation to produce relatively heavy residuum, gasoline-containing pressurerdistillate, and uncondensed gases, passing the liquid distillate into a body of adsorptive material wherein polymers are formed, allowing relatively high-boiling polymers to gravitate Within the liquidv distillate in said body of material toward the bottom thereof, separately withdrawing from said body of material a stream of said distillate having relatively low polymer content and a stream of the distillate that is relatively high in polymer content, recirculating saidrelatively high polymerv content stream of the A"distillate to said cracking zone, passing through a heating Zone a stream of solvent oil having a boiling range substantially higher than that of thegasoline content of the pressure distillate, mixing the heated solvent oil with said relatively low polymer content stream of the polymerized pressure distillate, vaporizing and separating the gasoline from the unvaporized solvent oil' in a vaporizing zone, thereby leaving gum-forming and sulphur-containing impurities of the distillate in said solvent oil, and passing said lsolvent oil from the vaporizing Zone to said cracking zone as preheated charging stock. 

